A Houston woman opened a box of medicine only to find the pills inside the box weren't the correct ones. Now you may want to double check your medicine cabinet.

When Sanaz Behrooz felt under the weather she went to a Target pharmacy for Sudafed.

"When I paid for it, she put it in the bag, so I didn't see it. I didn't check it," Behrooz said.

At home, Behrooz says she discovered an open Sudafed box with one empty pill sheet and another half-sheet containing children's probiotics.

"I was really shocked," she said. "I checked the package and it was open and I was like, 'Oh my God!'"

"Obviously, you want to know that you're getting the right medication," said ER Doctor Michael Chang.

Dr. Chang says it's up to you to check what you're buying, so you don't inadvertently take the wrong pills, especially if you have allergies.

Oftentimes, these are mistakes not because of intention, but due to human error.

It could be as benign as probiotics or more dangerous like blood thinners or unnecessary antibiotics.

"They're not just detrimental to you but also detrimental to the people who should've gotten the medication that you were written for," said Behrooz. "Maybe someone cannot read it. Maybe it's wrong medication. Maybe somebody's stealing from their pharmacy."

Behrooz, who is in the health care field, alerted the store manager. She says, the manager offered her a new box of Sudafed and her money back. What she wants most is for this not to happen again.

"It's a dangerous medication and they can make drugs with that, that's what I was concerned about," she said.

The Target store manager told Eyewitness News over the phone, this is a rare situation and if medications are ever returned, they're automatically destroyed and processed out of the system, so he has no idea how this could have happened.